Reformat space tuples if space format is changed

Now there's a lot a cases when a space receives new format, but its tuples continue to exist with old format. Examples:

• New index is added. If the index uses field that was not used by indexes before, the new format of the space will have an additional field slot with offset of that field. Meanwhile all existing tuples will remain in space with old format.
• External features, like tuple compression, can be dynamically turned on/off on a space, leaving all tuples unchanged. That leads to two problems: 1) enabling compression doesn't have immediate effect and 2) disabling the feature doesn't allow to switch indexes to more optimal virtual functions.
• Functional indexes are not able to make changes in tuples and have to store function result right in index. I'm not saying that it's bad, but perhaps that approach should be re-evaluated in terms of this issue.

We also should be careful and don't reformat tuples if there's no need to do that. Also perhaps at some cases we must do right in requested operation (before returning success to user) and at some cases - reformat in the background.

The issue does not name files, tests, or entry points. Start by tracing space format changes, tuple storage, indexes, and tuple compression; define when tuples must be reformatted immediately versus in the background, and verify that unchanged tuples are not reformatted unnecessarily.